In the past, in a wireless system, there is a case in which, when a plurality of wireless terminals perform transmission of data using same wireless resources (frequency and time), interference arises from collision of the data, resulting in failure in reception of the data at the reception side. Therefore, where a plurality of wireless terminals that use a same frequency exists, it is desirable to provide a contrivance by which one wireless terminal can occupy the frequency as far as possible within a certain time band to transmit data so as to prevent collision of data.
As a technology for providing such a contrivance as described above, for example, a technology is available which avoids collision using carrier sense. In this technology, a wireless terminal enters, before data transmission, into a reception mode, in which it measures reception power in a frequency channel to be used (hereinafter referred to also as channel). Then, the wireless terminal decides the measured reception power with a threshold value and suppresses transmission until an available wireless resource is confirmed thereby to avoid collision of data. The threshold value is hereinafter referred to also as carrier sense level. In order to suppress transmission to avoid collision or conversely avoid excessive suppression of transmission in this manner, a technology for setting a carrier sense level appropriately is demanded.
Therefore, for example, a wireless communication apparatus has been proposed in which media access is performed efficiently by temporarily changing the carrier sense level (for example, refer to PTL 1).